#include <iostream>
#include <Eigen/Dense>

using namespace std;
using namespace Eigen;

int main()
{
  Matrix2d a;
  a << 1, 2, 3, 4;

  Vector3d v(1, 2, 3);

  cout << "a * 2.5 =\n"
       << a * 2.5 << endl;
  cout << "0.1 * v =\n"
       << 0.1 * v << endl;
  cout << "Doing v *= 2;" << endl;
  v *= 2;
  cout << "Now v =\n"
       << v << endl;

  return 0;
}
